I've been researching previous posts on the topics mentioned above. Seems like the general buzz is Sia may last longer, but seems harder to find (heard about grizzly and bowlingbeat).
Also looking for info on CAB blocks vs SMT (I have a spinner, and the SMT looks uncomfortable to hold).

Updated comments in the Abralon/Sia debate would be appreciated.
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Signature? I dont need no stinking signature...

Abralon vs Sia. Cab vs SMT. The debate is on.
   I have heard that Sia lasts longer than Abralon.  Depends on how much pressure you apply, how long you sand with a particular pad, whether wet sanding or dry sanding. It has been my experience that if you wet sand, they both last about the same length of time or # of sandings. (I don't reccommend dry sanding unless the ball is really trashed and I want to take a lot of surface off fast. I use  only the courser grits, i.e.. 180, 240 or 360). When I am done resurfacing a ball, I rinse the residue from the pads under running water in the sink and lay them aside to dry.
   I have a ball spinner also. There are several things I like about the SMT (SMart Pro from www.polishyourball.com). First is how clean it is to use. My spinner sets on a bench in the garage. No splatter shield, no tub. With the SMT and an Abralon or Sia pad, all that is needed to wet sand is 3 or 4 light sprays of water with a squirt bottle in the center of the pad at first and then just a couple more sprays as you do each additional side of the ball with the same pad. The SMT and the sanding pads (which have a foam interior)help to keep the water on the surface of the ball, not flying through the air all over the place. Another thing I like about the SMT is you can use two hands and apply as much pressure as you want. I hold the SMT between my thumb and index finger,in the web of my hand. My hand just lays on top. You don't hold onto the handle like a door knob. Another plus, with the polishing bonnet slipped over the cup, I can lightly polish or really burn it in. Hopes this helps.